Abstract

In this paper, synthesis, characterization and detection of CN⁻ by the compound (N′1E,N′2E)-N′1,N′2-bis((2-hydroxynaphthalen-1-yl)methylene)oxalohydrazide (1) have been reported. Compound 1 is synthesized by the reaction of oxalyldihydrazide and 2-hydroxy-1-naphthaldehyde and characterized by FTIR, ¹H NMR and ESI-Mass spectroscopy. UV–Visible spectral band of 1 is observed to be broadened and shifted to longer wavelength upon addition of CN⁻ ion selectively in H₂O-DMSO (8:2 v/v) medium. Based on the UV–Visible spectral data, the detection limit of cyanide ion for 1 is found to be 30.2 μM. Colourless solution of 1 changes to yellow in the presence of cyanide ion selectively. The same colour change is also observed on Whatman filter paper test strip. Fluorescence intensity of 1 is quenched due to the nucleophilic addition reaction of cyanide with one of the two imine carbons. ¹H NMR titration of 1 with CN⁻ ion corroborates the reaction of the latter with one of the two imine carbons of the former, leading to the appearance of cyanomethyl proton signal at 6.15 ppm and consequently, its behaviour as chemodosimeter. The above mentioned chemodosimeter nature of 1 is also validated by ESI-Mass spectroscopy data. Compound 1 is capable for the detection of CN⁻ in water for real samples with concomitant colour change.

Graphic abstract

Compound 1 behaves as selective cyanide chemodosimeter with associated change in its colour (in solution and on Whatman filter paper test strip) and fluorescence. ¹H NMR titration and ESI-Mass data confirm the nucleophilic addition reaction of cyanide with 1. Compound 1 can be used for the detection of CN⁻ in water for real samples.

中文翻译：

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试纸上水介质中的氰化物选择性化学计量仪及其在实际样品分析中的应用

摘要

在本文中，合成，表征和CN的检测^-通过化合物（N'1E，N'2E）-N'1，N'2双（（2-羟基萘-1-基）亚甲基）oxalohydrazide（1）已经报道。通过草酰二酰肼与2-羟基-1-萘醛的反应合成化合物1，并通过FTIR，¹ H NMR和ESI-质谱进行表征。的紫外-可见光谱带1被观察到的扩大和在加入CN的偏移到更长的波长^-离子选择性H中₂ -O-DMSO（8:2 V / V）的培养基。根据紫外可见光谱数据，氰化物离子的检出限为1，为30.2μM。1的无色溶液在氰化物离子存在下选择性地变为黄色。在Whatman滤纸测试条上也观察到相同的颜色变化。由于氰化物与两个亚胺碳之一发生亲核加成反应，荧光强度1被淬灭。^1个的1 H NMR滴定1与CN ^-离子证实后者与前者的两个亚胺碳之一的反应中，在6.15 ppm的，因此，其作为chemodosimeter行为导致氰基甲基质子信号的外观。的上述性质chemodosimeter 1也通过ESI-质谱数据验证。化合物1是能够用于检测CN的^- 在水中用于伴随颜色变化的真实样品。

图形摘要

化合物1表现为选择性氰化物化学计量仪，其颜色（在溶液中和在Whatman滤纸试纸上）和荧光都有相应的变化。¹ 1 H NMR滴定和ESI-质谱数据证实与1.化合物1氰化物亲核加成反应可以用于检测CN的^-在水中实际样品。